6,866 research outputs found
Electromagnetic modes of Maxwell fisheye lens
We provide an analysis of the radial structure of TE and TM modes of the
Maxwell fisheye lens, by means of Maxwell equations as applied to the fisheye
case. Choosing a lens of size R = 1 cm, we plot some of the modes in the
infrared range.Comment: 2+6 pages in Latex, 3 figures to be found in the published referenc
Dijet Cross Section and Longitudinal Double Spin Asymmetry Measurements in Polarized Proton-proton Collisions at \sqrt{s}=200 GeV at STAR
These proceedings show the preliminary results of the dijet cross sections
and the dijet longitudinal double spin asymmetries A_LL in polarized
proton-proton collisions at \sqrt{s} = 200 GeV at the mid-rapidity |eta| < 0.8.
The integrated luminosity of 5.39 pb^{-1} collected during RHIC Run-6 was used
in the measurements. The preliminary results are presented as functions of the
dijet invariant mass M_jj. The dijet cross sections are in agreement with
next-to-leading-order pQCD predictions. The A_LL is compared with theoretical
predictions based on various parameterizations of polarized parton
distributions of the proton. Projected precision of data analyzed to date from
Run-9 are shown.Comment: 8 pages, 5 figures, Proceedings of the SPIN2010 conference (Juelich,
Germany, 2010
Uniformization, Calogero-Moser/Heun duality and Sutherland/bubbling pants
Inspired by the work of Alday, Gaiotto and Tachikawa (AGT), we saw the
revival of Poincar{\'{e}}'s uniformization problem and Fuchsian equations
obtained thereof.
Three distinguished aspects are possessed by Fuchsian equations. First, they
are available via imposing a classical Liouville limit on level-two null-vector
conditions. Second, they fall into some A_1-type integrable systems. Third, the
stress-tensor present there (in terms of the Q-form) manifests itself as a kind
of one-dimensional "curve".
Thereby, a contact with the recently proposed Nekrasov-Shatashvili limit was
soon made on the one hand, whilst the seemingly mysterious derivation of
Seiberg-Witten prepotentials from integrable models become resolved on the
other hand. Moreover, AGT conjecture can just be regarded as a quantum version
of the previous Poincar{\'{e}}'s approach.
Equipped with these observations, we examined relations between spheric and
toric (classical) conformal blocks via Calogero-Moser/Heun duality. Besides, as
Sutherland model is also obtainable from Calogero-Moser by pinching tori at one
point, we tried to understand its eigenstates from the viewpoint of toric
diagrams with possibly many surface operators (toric branes) inserted. A
picture called "bubbling pants" then emerged and reproduced well-known results
of the non-critical self-dual c=1 string theory under a "blown-down" limit.Comment: 17 pages, 4 figures; v2: corrections and references added; v3:
Section 2.4.1 newly added thanks to JHEP referee advice. That classical
four-point spheric conformal blocks reproducing known SW prepotentials is
demonstrated via more examples, to appear in JHEP; v4: TexStyle changed onl
PT-Symmetric Quantum Theory Defined in a Krein Space
We provide a mathematical framework for PT-symmetric quantum theory, which is
applicable irrespective of whether a system is defined on R or a complex
contour, whether PT symmetry is unbroken, and so on. The linear space in which
PT-symmetric quantum theory is naturally defined is a Krein space constructed
by introducing an indefinite metric into a Hilbert space composed of square
integrable complex functions in a complex contour. We show that in this Krein
space every PT-symmetric operator is P-Hermitian if and only if it has
transposition symmetry as well, from which the characteristic properties of the
PT-symmetric Hamiltonians found in the literature follow. Some possible ways to
construct physical theories are discussed within the restriction to the class
K(H).Comment: 8 pages, no figures; Refs. added, minor revisio
Role of Reactive Oxygen Species in the Neural and Hormonal Regulation of the PNMT Gene in PC12 Cells
The stress hormone, epinephrine, is produced predominantly by adrenal chromaffin cells and its biosynthesis is regulated by the enzyme phenylethanolamine N-methyltransferase (PNMT). Studies have demonstrated that PNMT may be regulated hormonally via the hypothalamic-pituitary-adrenal axis and neurally via the stimulation of the splanchnic nerve. Additionally, hypoxia has been shown to play a key role in the regulation of PNMT. The purpose of this study was to examine the impact of reactive oxygen species (ROS) produced by the hypoxia mimetic agent CoCl2, on the hormonal and neural stimulation of PNMT in an in vitro cell culture model, utilizing the rat pheochromocytoma (PC12) cell line. RT-PCR analyses show inductions of the PNMT intron-retaining and intronless mRNA splice variants by CoCl2 (3.0- and 1.76-fold, respectively). Transient transfection assays of cells treated simultaneously with CoCl2 and the synthetic glucocorticoid, dexamethasone, show increased promoter activity (18.5-fold), while mRNA levels of both splice variants do not demonstrate synergistic effects. Similar results were observed when investigating the effects of CoCl2-induced ROS on the neural stimulation of PNMT via forskolin. Our findings demonstrate that CoCl2-induced ROS have synergistic effects on hormonal and neural activation of the PNMT promoter
Spin Information from Vector-Meson Decay in Photoproduction
For the photoproduction of vector mesons, all single and double spin
observables involving vector meson two-body decays are defined consistently in
the center of mass. These definitions yield a procedure for
extracting physically meaningful single and double spin observables that are
subject to known rules concerning their angle and energy evolution. As part of
this analysis, we show that measuring the two-meson decay of a photoproduced
or does not determine the vector meson's vector polarization, but
only its tensor polarization. The vector meson decay into lepton pairs is also
insensitive to the vector meson's vector polarization, unless one measures the
spin of one of the leptons. Similar results are found for all double spin
observables which involve observation of vector meson decay. To access the
vector meson's vector polarization, one therefore needs to either measure the
spin of the decay leptons, make an analysis of the background interference
effects or relate the vector meson's vector polarization to other accessible
spin observables.Comment: 22 pages, 3 figure
General Aspects of PT-Symmetric and P-Self-Adjoint Quantum Theory in a Krein Space
In our previous work, we proposed a mathematical framework for PT-symmetric
quantum theory, and in particular constructed a Krein space in which
PT-symmetric operators would naturally act. In this work, we explore and
discuss various general consequences and aspects of the theory defined in the
Krein space, not only spectral property and PT symmetry breaking but also
several issues, crucial for the theory to be physically acceptable, such as
time evolution of state vectors, probability interpretation, uncertainty
relation, classical-quantum correspondence, completeness, existence of a basis,
and so on. In particular, we show that for a given real classical system we can
always construct the corresponding PT-symmetric quantum system, which indicates
that PT-symmetric theory in the Krein space is another quantization scheme
rather than a generalization of the traditional Hermitian one in the Hilbert
space. We propose a postulate for an operator to be a physical observable in
the framework.Comment: 32 pages, no figures; explanation, discussion and references adde
Enhanced dispersion interaction in confined geometry
The dispersion interaction between two point-like particles confined in a
dielectric slab between two plates of another dielectric medium is studied
within a continuum (Lifshitz) theory. The retarded (Casimir-Polder) interaction
at large inter-particle distances is found to be strongly enhanced as the
mismatch between the dielectric permittivities of the two media is increased.
The large-distance interaction is multiplied due to confinement by a factor of
at zero temperature, and by
at finite temperature, \gamma=\ein(0)/\eout(0)
being the ratio between the static dielectric permittivities of the inner and
outer media. This confinement-induced amplification of the dispersion
interaction can reach several orders of magnitude.Comment: 4 page
Products of Vitamin D3 or 7-Dehydrocholesterol Metabolism by Cytochrome P450scc Show Anti-Leukemia Effects, Having Low or Absent Calcemic Activity
BACKGROUND. Cytochrome P450scc metabolizes vitamin D3 to 20-hydroxyvitamin D3 (20(OH)D3) and 20,23(OH)2D3, as well as 1-hydroxyvitamin D3 to 1a,20-dihydroxyvitamin D3 (1,20(OH)2D3). It also cleaves the side chain of 7-dehydrocholesterol producing 7-dehydropregnenolone (7DHP), which can be transformed to 20(OH)7DHP. UVB induces transformation of the steroidal 5,7-dienes to pregnacalciferol (pD) and a lumisterol-like compounds (pL). METHODS AND FINDINGS. To define the biological significance of these P450scc-initiated pathways, we tested the effects of their 5,7-diene precursors and secosteroidal products on leukemia cell differentiation and proliferation in comparison to 1a,25-dihydroxyvitamin D3 (1,25(OH)2D3). These secosteroids inhibited proliferation and induced erythroid differentiation of K562 human chronic myeloid and MEL mouse leukemia cells with 20(OH)D3 and 20,23(OH)2D3 being either equipotent or slightly less potent than 1,25(OH)2D3, while 1,20(OH)2D3, pD and pL compounds were slightly or moderately less potent. The compounds also inhibited proliferation and induced monocytic differentiation of HL-60 promyelocytic and U937 promonocytic human leukemia cells. Among them 1,25(OH)2D3 was the most potent, 20(OH)D3, 20,23(OH)2D3 and 1,20(OH)2D3 were less active, and pD and pL compounds were the least potent. Since it had been previously proven that secosteroids without the side chain (pD) have no effect on systemic calcium levels we performed additional testing in rats and found that 20(OH)D3 had no calcemic activity at concentration as high as 1 µg/kg, whereas, 1,20(OH)2D3 was slightly to moderately calcemic and 1,25(OH)2D3 had strong calcemic activity. CONCLUSIONS. We identified novel secosteroids that are excellent candidates for anti-leukemia therapy with 20(OH)D3 deserving special attention because of its relatively high potency and lack of calcemic activity.National Institutes of Health (R01A052190
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